A huge joint U.S.-Israeli missile defense exercise has been postponed, churning up speculation that the delay is a result of growing tensions over Iran’s nuclear program, Reuters reports.

The Austere Challenge 12 drill, originally scheduled to take place in April and meant to strengthen U.S.-Israel military cooperation, has been pushed back until the second half of 2012, and as Reuters reports, Israeli media had initially said that the cancellation was due to budgetary constraints.

But as speculation grew that Iran’s nuclear program was at the root of the exercise’s sudden cancellation, American and Israel officials have both denied to news outlets that escalating tensions with Iran were the reason.

“It’s for a host of reasons, mainly logistical, but not the reason you cited [tensions with Iran],” an Israeli official told Reuters.

Similarly, Pentagon spokesman Navy Captain John Kirby also downplayed reasons for the drill’s delay, saying such a postponement was not uncommon.

“There were a variety of factors at play in this case, but in general, leaders from both sides believe that optimum participation by all units is best achieved later in the year,” Kirby said, according to Reuters.

In a speech in Washington, D.C., last month, Defense Secretary Leon Panetta had hailed the joint exercise as a demonstration of the Obama administration’s “unprecedented levels of defense cooperation with Israel to back up our unshakable commitment to Israel’s security.”

The enhanced defense capabilities “are themselves a product of this unprecedented defense cooperation,” said Panetta.